Field of the Invention
The present invention relates to an imaging apparatus and a method for controlling the same.
Description of the Related Art
As a focus detection method for controlling the focusing of an imaging apparatus, there is a technique that performs phase difference-type focus detection simultaneously with imaging by applying a configuration such that a pixel in an imaging element receives light from a different pupil plane of an imaging lens.
Japanese Patent Laid-Open No. 2001-083407 discloses an imaging apparatus in which a light-collecting photodiode (hereinafter referred to as “PD”) is divided into a plurality of PDs under one micro lens and each of the PDs receives light from a different pupil plane of an imaging lens. The imaging apparatus compares outputs from the two PDs to thereby perform focus detection. The imaging apparatus disclosed in Japanese Patent Laid-Open No. 2001-083407 performs focus detection using the output of an imaging element for imaging an image. Thus, when the imaging apparatus is applied to a typical color camera or the like, each pixel of the imaging element has a color filter. In this case, a color signal which is different for each arrangement of color filters is obtained as a focus detection signal.
Here, there has been proposed a technique that performs focus detection using an output signal from an imaging element in which a color filter is provided for each pixel. Japanese Patent Laid-Open No. 2000-292686 discloses an imaging apparatus that includes an imaging element having pixel portions in which a color filter is provided for each phase-difference detection pixel and performs phase difference detection using an output signal from the pixel portion.
However, the imaging apparatus disclosed in Japanese Patent Laid-Open No. 2000-292686 calculates a focus detection signal by using focus detection data from a blue filter and a green filter, separately, which are adjacent in the horizontal direction to thereby average the calculation result. In the method, calculation needs to be performed for each color filter, resulting in an undesirable increase in the amount of calculation for focus detection.
In addition, the imaging apparatus disclosed in Japanese Patent Laid-Open No. 2000-292686 has an output line in only one row as the output line of a focus detection signal. Thus, in the imaging apparatus, when the output line of a focus detection signal is set in plural and focus detection signal calculation processing is performed in the vertical direction in the same manner as that in the horizontal direction, the amount of calculation further undesirably increases. Furthermore, in the imaging apparatus, a color filter of the same color is arranged in every second pixel, so that the amount of data for focus detection reduces, resulting in a decrease in focus detection performance.